Quote:
Originally Posted by maxhifi
May have an opportunity to bring home a Sharp 75" TV, I would estimate it is 5 years old. Problem as follows:
Off state: Blue power LED is slowly flashing
Turn on with remote: Blue power LED comes on solid, LCD screen comes on, and displays SHARP logo. Screen flashes, and then set goes dead completely, does not respond to remote control. A short while later, the blue power LED starts flashing slowly again, and the set will respond to another cycle.
Based on above, does it sound like this set can be salvaged? I am assuming it is a power supply issue, which is encouraging, but I've never worked on an LCD TV before.
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Model number?
We see an inordinate amount of LED issues with most TVs 5 years and newer, and the newer they are, the more LED problems they have.
I use an LED tester that can "ring" the strings and provide a running voltage for 20ma worth of input (LEDs are powered by a regulated current, the voltage reading depends on the number of LEDs used and the condition of them).
If the TV has two or more strings of LEDs, we can measure the differences between the strings, assuming of course that each string is driving the same number of LEDs, and not all TVs do.
So, if you have a string of LEDs out, the controller IC will detect an undercurrent and either shut down that one string (unusual) or the whole array (more common). Also, a single shorted LED or a single weak LED that is dropping more than it's 3V or 6V rating can trip the LED circuit to shutdown if it's configured to be hair trigger.
John